Easy fixes for gas mower starting issues

A gas mower that won't start doesn't necessarily mean a it's time for a new machine. Major repairs are best left to the professionals, but many minor issues can be fixed at home.

Check the fuel and electrics

If the engine won't turn over, first check the spark plug, then try these simple fixes for your ignition and fuel systems.

• If your mower starts with a push button rather than a pull cord, disconnect the battery and clean its contacts with a wire brush to remove any corrosion. Fully charge the battery using the charger supplied with the machine, and try to restart.
• If you have a riding mower, sit on its seat before attempting to start the engine. These mowers have a safety cutoff switch in the seat that allows the engine to start only if someone is at the wheel.
• Open the gas cap and have a sniff: if it smells sweet like turpentine then the fuel has gone bad. Slowly tip the mower on its side and empty the tank into a tray before refilling it with fresh fuel.

Try cleaning or changing the spark plug

When you pull on the mower's pull cord, but the engine just won't turn over, there's a good chance that your spark plug is at fault.

Sometimes, the plug just needs a good clean, but it's always worth keeping a spare in case you need to install a replacement. Consult your owner's manual for the specifications, or remove the plug from your machine and take it to a DIY store or garden centre to ensure a match; buy a second spare for next time, too.

Time needed to change a spark plug: 15 minutes.

Tools needed: spark plug, spark plug socket or wrench, clean rag, rubbing alcohol and a wire brush.

• Make sure the engine is cold, then find the spark plug. It's usually at the front of the mower, capped with a rubber connector. Disconnect the lead and, using a clean rag, wipe around the base of the plug, where it enters the engine.
• Use a wrench, or a spark plug socket, to unscrew the plug, and then remove the plug fully from the mower. The electrode at the tip of the plug will probably be blackened. Try to remove these charred deposits with a wire brush and a cloth soaked in rubbing alcohol. If they won't budge, or if the body of the plug is cracked, replace it with a new one.
• Screw in the new or cleaned spark plug with your fingers, then give it a light turn with a wrench or spark plug socket, taking care not to overtighten. Reattach the plug lead and start up your mower.

Before working on your gas mower, switch off the engine, disconnect the spark plug and let the unit cool down. Wear protective gloves and use a stick, rather than your hands, to remove any obstructions near the blades.

If you can't get the engine started, or if it runs with excessive smoke despite your best efforts, take it to your repair centre. If the mower needs a new engine, it's probably time to invest in a new machine. Rust can also kill a mower by eating through the deck; almost all other problems can be fixed or avoided through good maintenance.